Raman scattering or the Raman Effect is an inelastic photon scattering phenomenon. When photons are scattered from an atom or molecule, most photons are elastically scattered (Rayleigh scattering), such that the scattered photons have the same energy (frequency and wavelength) as the incident photons. A small fraction of the scattered photons (approximately 1 in 10 million) are scattered by an excitation, with the scattered photons having a frequency different from, and usually lower than, that of the incident photons. In a gas, Raman scattering can occur with a change in energy of a molecule due to a transition to another (usually higher) energy level.
Raman Effect (Raman shift) is exhibited in almost organic molecules including not only by polar molecules but also by non-polar molecules which have induction polarizability when Raman spectroscopy using Raman scattering is applied. It is thus more suitable for the detection of biomolecules such as proteins, genes and the like since it is not affected by interference caused by water molecules.
On the other hand, specific wavelengths of Raman emission spectrum represents chemical composition and structure features so that it can be used to directly analyze materials using Raman signals.
Surface enhanced Raman scattering is associated with surface plasmon resonance phenomena caused with excitation by electromagnetic radiation. Signal intensities are greatly amplified with the electromagnetic resonance.
It has been studied in a variety of structures for inducing this surface enhanced Raman scattering, and recently technologies relating to substrates for surface enhanced Raman scattering are being developed with utilization metal nanoparticles or metal nanowires.
Ag nanowire arrays by a glass capillary: A portable, reusable and durable SERS substrate in Scientific Reports 2, Article number: 987, doi: 10.1038/srep00987 discloses a technique for aligning Ag nanowires along the direction of a capillary on the inner wall of the capillary.
Assembly of Ag Nanowires into 3D Woodpile-like Structures to Achieve High Density Spots for Surface-Enhanced Raman Scattering in Langmuir, 2013, 29 (23), pp 7061-7069, DOI: 10.1021/la4012108 discloses a method for alternatively laminating Ag nanowires according to the Langmuir-Blodgett method.
KR Patent No. 10-1073853 discloses a manufacturing method of a nano structured net-shaped film on a substrate. It teaches a method for forming the nano structure by a filtration method. However, it requires a transcription process after filtration and does not teach its application as a substrate for surface enhanced Raman scattering. It discloses that the nano substrate is a carbon nanotube which is manufactured by transcription of a membrane in which the nano structure net-shaped film is formed on the substrate such as a silicon oxide and then separating the membrane using surface tension difference between the membrane and the substrate (FIG. 1). Thus, its technical field is different from a substrate for surface enhanced Raman scattering of the present disclosure.
US Patent Publication No. 2012-0300203 discloses a method for the formation of a substrate with filtering capabilities by utilizing a nanoparticle ink. This teaches that nanoparticles with much smaller size than a fiber strand are densely adhered on a fiber strand which is a part of the substrate with filtering capabilities.
The present disclosure is to provide a substrate for surface enhanced Raman scattering which is prepared by using filtering functions and is able to suitable for Raman signal analyses, a fabricating method for the same and an analyzing method using the same.